Quote: "Never thought a video card could do so much to your performance. "
Neither did I. Thankfully Richard and some other nice folk on the board recommended upgrading that over other things. I'm glad I listened.
Quote: "I don't know much about a computer's hardware so I don't know what a AGP slot is, I probably don't have it cos my computer is about 4-5 years old."
AGP has been around for a while. If you have a pentium processor there is a good chance you have one (not always - my cheapo Dell does not have one). Try this link:
http://www.crucial.com/kb/answer.asp?qid=3994
When in doubt just make sure you get a PCI card (NOT PCI Express which is a newer kind of slot I guess)
If you decide to use newegg.com you can sort video cards by RAM size, slot t ype, etc. so you can filter out what you need. I'll try to give you a link to exactly what I purchased, but I don't know if the link will work right:
http://www.newegg.com/app/ViewProductDesc.asp?description=14-145-087&depa=1
PS - turns out the card was $95 + $3 S&H (not $94... was off a dollar!?!)
Quote: "Is it hard to install the card into your computer?"
It is without a doubt the single easiest thing to do on a computer. Even RAM can be more difficult becuase you may have to tilt the ram a certain way, apply hard pressure, etc.
With a PCI video card all you do is open your case and look in the back for the line of slots (make sure computer is off). Find a free one (if there is already a video card there you should remove it - you can tell because the monitor cable will run to it - chances are you have an "onboard" video card so you need not worry about it). The cards in the back are held in by a single screw easily taken out with a phillips head screwdriver. You put the new card in (it only fits one way) and apply a litle gentle pressure to make sure the card slides into the slot. Put the screw back in and attach your monitor to the back of the new card. Viola! You are done. (ummm well you do have to turn the computer back on first)
The ONLY snag is if your computer has some weird onboard video card that won't automatically disable in favor of the new card. If that happens you will have to crack out your books, call tech support, get a friend to look at it, etc. because there will be some weird BIOS setting, dip switch or jumper that has to be changed somewhere. This is pretty uncommon though and chances are you won't have this kind of problem.
I'm sure someone more technically inclined may chime in here and offer other advice, but it all sounds much harder reading about it than actually doing it. You would have more trouble replacing the battery in your car then swapping out a new video card. :-P
Good luck and happy zombie killing!